uses relay or electronic switching between TX and RX?
while listening to a signal, unplug the mike. If you can still hear something, it’s relay switched. If the speaker goes dead but the S/RF meter still shows a signal there, you have electronic or diode switching.
electronic switching requires at least four wires.
Relay switching is generally easier to wire up, because you only need three connections: Mike Audio, Ground, and the TX Keyline that energizes the relay when Grounded.
Electronic switching uses four wires: a common Ground, Mike Audio, TX Keyline that switches to TX when Grounded, and RX speaker line that opens the speaker on TX to prevent feedback squeal.